Wire Strikes

[RockyMountainPilot]

I am posting this because of the recent medical helicopter crash, but I felt it shouldn't be in that thread.

 

I still hear too many pilots talk about keeping airspeed to the ground during confined area approaches. Forget that. Go in vertical, leave vertical. Too many worries about engine failures in the HV curve when that isn't even a major killer. Yeah, the helicopter is going to be toast if the engine quits, so be just be prepared to drop the collective, and pull into into your armpit before contact with the ground. Wire strikes are the number one killer, so avoid them like the plague. Engine failures in the HV curve are extremely rare, and if you are well prepared you will walk away. Play the odds.

[joeschmoeheli]

What about settling with power? LTE? Low Rotor RPM when you lose ground effect?

 

Where are the winds? How much do you weigh? How much power reserve do you have?

 

Forward airspeed is your friend for many more reasons than just engine failure. If you have a good wind then a steeper approach might be acceptable but in variable/gusty winds you can get into trouble with a steep or vertical approach.

 

I say a good high and low recon is your best friend. Always look for wires and if possible do a ground recon first. If you have contact with someone on the ground then get their view too.

 

Every approach is different because there are a million different variables that effect your decision of what kind of approach to use.

 

Maybe I misunderstood your question but hope this helps.

[Wally]

I can't count the number of times I've seen stuff flash by underneath the aircraft departing an LZ, that I didn't see on the high, low or ground recon. That's pretty scary, enough for me to continue vertical in and out. I know lots of guys who've survived emergencies from the deadman zone, and very few who survived wire strikes.

If you can't do the vertical, you'd better cover all bets and have a very good reason to risk your life.

[Darren Hughes]

Funny you should mention that, I failed my CFI check ride once for flying the typical pattern that our school taught to a confined area/pinnacle. Basically for most of our final leg we were just above ETL all the way down to the spot. One of the reasons we taught it like this was to give us a better chance to spot wires & obstacles on the way into the spot, and with slower speed we would have more time to react to the situation. Our Chief pilot said that the high recon may not show all the dangers of the landing area, and that certain things that you may dismiss on that high recon may come with a different perspective on the low recon(or final approach).

 

Now, on the check ride the FAA guy, who was an Ex Marine-Cobra pilot, had me teach 2 approaches my way to a spot and then proceeded to take the controls and fly his own which was pretty much the same as mine except with 60-70kts on final all the way down to 50-100 feet(can't remember now cause I've purged this craziness from my mind) where he proceeded with a rapid deceleration while intercepting a 15 degree glide path down to the spot. I guess he would have quickstopped directly over the spot and came in vertical if there was trees or something just before the spot blocking the 15 degree glide path.

 

Needless to say, I was pissed when I seen what he wanted me to teach(although I contained myself all the way home with him). My Instructor was pissed as was the owner of the school who had never once heard of this FAA guy wanting this maneuver flown like this. The next week I went out with him and flew the approach the way he wanted, my full down was as smooth as a babies bottom and I passed no problems. I've never taught his way since and I don't think I ever will unless someone gives me a good argument for doing it like this apart from coming into a "hot LZ"!!

 

So RockyMountainPilot, what height do you want to come in vertical from. Ooh and sorry for hijacking with my little rant. I just thought I'd show that there are so many different ways to skin this cat(well from teaching in a school point of view anyway, maybe not the real world), it's gonna be difficult to find the right one.

[CFIAP5544]

Vertical is Great if you have the power and can avoid settling with power.

[RockyMountainPilot]

Darren,

 

That is the problem with examiners. They all have their opinions on what is best. I have been on a lot of checkrides, and most examiners don't even know the rules for examiners. It can be very frustrating, and if you complain to the FAA, they don't do anything. That is why it is best to find examiners with good references from past applicants. I like to do a mock checkride with an examiner before I send any students to them. If you don't like them, you can FAIL them. LOL

 

I come in from whatever height is needed. If the tree line is 50 feet, then it will be 50 feet. If it is a deep valley, that requires me to come in from 200 feet, then I come in from 200 feet. If there is an open field a half mile away, I make a normal approach and make them walk.

 

CFIAP,

 

If you don't have the power to do a vertical approach or departure into a confined area, then you shouldn't be landing there. I watch a tail go through the trees once when an instructor in an R22 lifted of with some forward speed and made it over the tree line of a confined area. However, there was a hill with higher trees and he wasn't going to make it over them. He slowed it up until he was in a hover, but didn't have enough power to maintain altitude and started to settle. He turned around as he descended, his tail went through the branches. Chewed that tail rotor up pretty good. He was lucky it didn't come apart.

 

Imagine if you were approaching a field, and you were just leaving ETL as you were pulling in full power. You notice that your LZ is full of tall thin weeds, or barbed wire fencing, swampy mud, etc. that you didn't see on your recons. You don't have any room to accelerate to depart, you can't hover OGE, and if you land, you will likely screw up the TR, damage the airframe, get stuck, or slip it over. What do you do? If you had the power to do a vertical descent, then you would be fine.

 

And I think you mean VRS, not settling with power. Settling with power is insufficient power to hover. VRS is entering your own vortices. You should know the minimum rate of descent that your helicopter will encounter VRS at minimum, and gross weights. You simply keep your ROD from coming close to that figure. And that is not a problem, because you want to descend very very slow so you and your crew can survey the area. I descend at about 100 fpm from a high hover.

[JDHelicopterPilot]

As I have just finished my EMS 135 training I have a much better understanding now. Many things taught in "school" are not "real" world. As others have said vertical in and out for the most part is what it is. It is also really really slow and a lot of communication with the crew if you have them with you.

 

Wires are hard to see. At night it's even harder. NVG's help but it's not the end all be all. Horizontal lines are hard for NVG's to pick up. Once down to 200'agl it's much better and then use the night sun search light to highlight the wires.

 

It's true every examiner has their way. If you can learn ahead of time what that is. However, the way you did it is the way that I think just about every school teaches it. A power check is a must when off airport.

 

As already said, it's more likely someone will hit something on the way down rather than having an engine failure in the curve. We need to minimize the most likely risk if we can't minimize them all.

[HelliBoy]

I agree with half the suggestion of vertical ascents/descents into confined areas when operating outside of a training environment. A vertical ascent is a fantastic maneuver if you've got the power and I agree that you've got a better chance of running into something than having an engine failure.

 

HOWEVER, a vertical descent is suicidal and an accident waiting to happen in IMHO. Think about what your argument for a vertical ascent is...you may not see whats in front of you with a forward takeoff so take off vertically and you'll be fine. Flip that statement over for an arrival. When descending vertically into an LZ you have ZERO chance of spotting an obstruction you missed on recon. Im pretty sure not everyone has doors off or bubble windows to lean out and look down either. I can think of nothing more dangerous than flying into a space you cant see and thats whats being suggested here, you might as well fly backwards too so the tail boom can absorb some of the impact. Unbeleivable.

 

Now on to the question of training for confined areas.

 

RMP- the story about the CFI pranging the tail rotor is a good one. Id relate it to CFIs who dont follow the proper procedure for confined areas. He made several mistakes. Why on earth would you go into a confined area and plan on exiting uphill into trees??? That is why he had an accident right there. He performed a wildly incorrect assesment of the area and its surrounds or didnt perform one at all.

Also- when he realized he'd made a bone head move he could've saved the situation by aborting the maneuver. Pulling into a hover and yanking up on the stick in your left hand is NOT aborting a max performance takeoff from a confined area. He should have realized he wasnt going to make it out as soon as he could see the trees beyond the confined area and either descended along the same flight path as he got there or 180'd back into the area.

 

Many, if not all light piston training helicopters have a marginal ability to HOGE or climb from an OGE hover without translational lift. This is true especially when there are two pilots on board. In my experience, a 300C will do it, a 300CBi might do it, and a 300CB or R22 will almost never do it. Thats not even mentioning arresting a zero airspeed descent with collective inputs alone.

However, a maximum performance takeoff can be performed up to 75 to 100 ft under most conditions and that is almost always enought to get out of a confined area and get ETL with forward motion.

I've heard no one yet mention power checks and a power check is the only way to know if you'll make it out or not. In a Schweizer I've found 2.5"-3" over hover MP is plenty for a MPT.

Now how do we decide to go into an area and know that we'll be able to get out of it?? If you can make a steep approach into an area you should be able to get out of it if you have the power as verified in your power check. A steep approach is defined in the RFH as 12 degrees. If youre setting up your approaches properly and using your sight picture then you know at the Approach Entry Point if you're going to be able to make a steep approach and thus a safe Max Performance takeoff. If you cant see your touchdown point using your sight picture reference when you start your approach then the correct action is to abort it and any DPE who fails you for it is a goon.

I disagree very strongly with teaching PPLs to fly confined areas in any other fashion- its easy for us to say 'oh I can do it' no problem. And we probably can. A student with 60 hours will evenually come to greif if they are taught that its okay to fly nonstandard confined area approaches. You dont have to be able to climb vertically with zero airspeed to do it safely either. You have to follow good procedure and develop good judgement.

 

A good rule of thumb for Maximum Performance Takeoffs: If you cant see the top of your obstrution below the rotor disk at your departure point then you are going to have a very hard time getting out of your confined.

 

I'm sorry for the long rant and I dont mean to sound disagreeable in my disagreement, but I almost choked on my sandwich reading some of the things posted.

[JDHelicopterPilot]

You have a point. I should have been more clear. It's nearly vertical. Not a 0 degree angle just steeper that a steep approach would be. So, we can clear our path on the way in. Also, I may keep a crab so I can see where I am going better. There may be times when we have to go vertical. That's just the way it is sometimes. Same thing for the way out. A good recon of the area esp. above and up we go.

[RockyMountainPilot]

Yeah, a vertical approach is one that is very very slow and well below ETL. I would say I usually come in at about an 85 degree angle at 100 fpm or less. I could run into powerlines, stop, and back off with the speed I come into an LZ. And I also come in crabbed at about 45 degrees. This gives me and my crew much better visibility.

 

Helliboy,

 

How do you know what your HIGE MP will be before you are actually in a HIGE? A much better way to do a power check is to enter a HOGE directly over your LZ and know what it will take to climb out with any extra payload. Of course when your crew or the on scene PM & FF suck at guesstimating a patients weight, you might have a wrench thrown into your calculations. LOL I would constantly hear 200 lbs and get a 280 pound dude laying next to me. Several times I have pulled 100% torque in a hover and just had to wait until we burned off some fuel. at 4 or 5 pounds a minute, it isn't long before you start climbing vertically.

 

One thing to watch for is any winds in your HOGE above your LZ. It could lower your torque reading, but once you are below tree line and have no wind, you don't have that help and can't take off vertically. Waiting for fuel to burn off, waiting for a lower density altitude, or making one of your crew get a ride to a bigger field are all options.

[Witch]

I had an instance where the area was a little small. The power check was about 22", and the max was about 24". It was tight getting in, but when it came time to leave, the trees seemed to grow about 20' almost instantainiously. Fearing a collision and noting little room to make a U-turn, I lifted up on the collective and cleared the trees by about ten feet. I think I pulled 25".

 

So I'm wondering if pulling more than the rated max might be an option if one needs to. It seems to me that it'd be OK as long as it's not done all the time. Or will it cause major damage that'll cause the engine to fall off?

 

Thoughts?

 

Later

[ADRidge]

So I'm wondering if pulling more than the rated max might be an option if one needs to. It seems to me that it'd be OK as long as it's not done all the time. Or will it cause major damage that'll cause the engine to fall off?

 

Thoughts?

 

Later

 

For me, it all boils down to how many zombies are in the confined area I'm leaving.

 

I wouldn't make a practice of pulling more than what is allowed, but you gotta do what you gotta do I suppose.

[Gomer Pylot]

VRS or settling with power is never an issue if you keep the descent rate low. I keep it between 200 & 300 fpm, for two reasons - I want time to see crap I might hit, and to prevent VRS. It's not possible to get VRS at that rate of descent, because the rotor wash is moving much faster. The more vertical the descent (and ascent) the less chance of hitting wires. I keep my approaches steep and slow, especially at night. Never ever get in a hurry. If you can't make the approach and departure below ETL, then you need to find out before you're completely committed, and the way to do this is get slow while still high, where you still can get the nose over and go around. Inside the confined area is way, way too late. Coming in hot and making a big flare is the most dangerous way you can make an approach, and IMO is stupid. There are lots of things in an unprepared confined area that can hurt you, and engine failure and VRS are at the bottom of the list.

[JDHelicopterPilot]

In an R-22 a 2" MP margin is not enough to go vertical in my opinion. I have a sheet somewhere with some good rule of thumb numbers. A few other things. It tends to be easier power wise to get in than to get out so keep that in mind.

 

Also, when going vertical on the way out without enough power you run the risk of power settling. This is not the same as SWP. This just means you don't have enough power to climb and hover at the altitude you got up to. So what happens? You settle back down and it may not be pretty depending on how bad it was.

 

I would never recomend pulling more than max allowed in order to get out of a spot. If I recall the R-22 has a limited MP chart. I don't know if pulling 25" exceeded the limits in your case or not. Many turbine helicopters and piston for that matter have a 5 minute take off limit. After that you are exceeding limits. Many will also have whats called a transient limit. It is mostly limited to 5-10 seconds in which you can pull that limit. However, the RFM will also state intentional use of the transient limit is not authorized. So you can't count on it.

 

It's important to look at your performance charts. HIGE and HOGE charts. I only use the HOGE charts unless I know I have a big open place where I can land on a smooth surface. Then I'll use the HIGE chart. While these are not limitation charts it gives you an idea as to the performance of the helicopter. Keep in mind wind and other factors will change performance in which the chart doesn't acount for. Last, a power check before comiting to the spot. Just as Gomer said.

 

I wanted to add one more thing I forgot. If you do pull more than your allowed power a lot, over time it will put excess stress on many items of the aircraft. Now, more than likely you are not the only pilot who flys that helicopter. If everyone did it all the time just inmagine how it can compound. While I hope it doesn't happen, I am sure there have been pilots whom have exceeded limits and didn't report that or notice for what ever reason. These days many newer helicopters have VEMDs or other type of engine computers which will actualy record any and all limits that were exceded.

 

Anyway, steep and slow at 200' ROD is the way to go.

Edited October 18, 2008 by JDHelicopterPilot

[Goldy]

Fearing a collision and noting little room to make a U-turn, I lifted up on the collective and cleared the trees by about ten feet. I think I pulled 25".

 

So I'm wondering if pulling more than the rated max might be an option if one needs to. It seems to me that it'd be OK as long as it's not done all the time. Or will it cause major damage that'll cause the engine to fall off?

 

Thoughts?

 

Later

 

Witch, pulling excess power in the 22 is quite doable. However, it all adds to the stress points on the aircraft (starting with the transmission, tail rotor gearbox, spindles, blades, etc) and it will lead to premature failure. So, when will the part fail? Hopefully not when I am flying the ship after you.

 

The Beta II does have a 5 minute power rating, where you can pull some extra HP for 5 minutes, this helps you get in the air...I use it all the time!

 

However, do NOT make any habit of pulling excessive power in the 22, it may not break now, but it will break....any you will never see it coming. Metal fatigue is invisible. By the time the tiniest of cracks appear your wife is already cashing in the insurance policy.

 

Goldy

[RockyMountainPilot]

If you need to exceed the power limitations to prevent from bending metal, then do it. What is the point in worrying about ten seconds of extra stress when a wrecked helicopter is much worse. And if the manufacture was worried about people over stressing the engine or tranny, they would require an inspection after pulling more than the limit. Robinson has no required inspection.

[JDHelicopterPilot]

If you need to exceed the power limitations to prevent from bending metal, then do it. What is the point in worrying about ten seconds of extra stress when a wrecked helicopter is much worse. And if the manufacture was worried about people over stressing the engine or tranny, they would require an inspection after pulling more than the limit. Robinson has no required inspection.

 

I didn't say you can't use it. Just not intentionaly. If it comes to it and all else fails then by all means use what ever you need to ensure the safety of your passengers. What I was refering to was the previous poster asked about exceeding the limits on a regular basis. That is a problem in several ways. Over stress is one. Another is that there is a bigger overlying problem if you find yourself having to exceed limits on a regular basis. Those of which I won't get into now.

[RockyMountainPilot]

Another is that there is a bigger overlying problem if you find yourself having to exceed limits on a regular basis. Those of which I won't get into now.

 

Are you calling some people fat? LOL

 

I think on most training flights in which I was a student or instructor, we pulled more than the limits at least one time, and sometimes several. This was in Robbies and 300's. We never had to perform any inspection, and the manufacturers are well aware of this. Exceeding the limit for a couple seconds won't do anything in these aircraft. It is when someone pulls over the limits for extended periods of time, like in cruise flight to go faster, that causes the problems.

[joeschmoeheli]

I think on most training flights in which I was a student or instructor, we pulled more than the limits at least one time, and sometimes several. This was in Robbies and 300's. We never had to perform any inspection, and the manufacturers are well aware of this. Exceeding the limit for a couple seconds won't do anything in these aircraft. It is when someone pulls over the limits for extended periods of time, like in cruise flight to go faster, that causes the problems.

 

You are wrong. It's bad for the drivetrain and all the components. The limits are there for a reason. If you are in an emergency then go ahead, pull all you can. But if you are regularly pulling over your MP limits you are putting undue stresses on the aircraft. This could cause components to fail in the future. Yeah, they are conservative estimates and you can pull more power but if you are training someone else that it is OK you are not doing your job very well and creating unsafe pilots. What happens when you get into a turbine ship and start pulling that sh*t?

 

Your argument of "I do it all the time and nothing happens to me" is retarded.

[Darren Hughes]

I think on most training flights in which I was a student or instructor, we pulled more than the limits at least one time, and sometimes several. This was in Robbies and 300's. We never had to perform any inspection, and the manufacturers are well aware of this. Exceeding the limit for a couple seconds won't do anything in these aircraft. It is when someone pulls over the limits for extended periods of time, like in cruise flight to go faster, that causes the problems.

 

In the training environment I think you should be "training" yourself and your student not to exceed those limitations set out by the manufacturer, isn't that the whole idea, so that when you get into your first turbine that you don't have even the slightest tendency to over-torque, unless you need to save the ship from a situation you probably shouldn't have gotten yourself into in the first place. If you're doing it from the start of your training and all the way through, you will be predisposed to looking at the gauges and not really respecting the red lines.

 

RMP, I guess it's easy to say that, but judging by your screen name you were probably operating at some pretty high density altitudes throughout your training. I still don't know if that's a good enough excuse for a CFI to exceed limitations at least once every flight.

[RockyMountainPilot]

Joeschmoe and Darren,

 

I have discussed this extensively with Schweitzer and Robinson reps. If they were worried about intermittent pulls of the MP beyond the limitations, they would have an inspection requirement. They don't.

 

And I guarantee you that I can take any instructor here, put them close to gross weight in an R22 or 300C, and catch them exceeding the MAP limits recovering from botched autos, or with a new student learning to hover, quick stops, etc. And I bet that instructor won't even know they exceeded the limits. So, anyone who says they never exceed the limits during training flight either isn't letting the student fly enough, or doesn't have the experience yet to know they are exceeding the limits. If a student is slow at getting on the power in a power recovery and the RPM drops even a little, the MAP has to go way beyond what it takes to hover to get that rpm back. The problem is, your eyes are not on the MAP gauge. They are either outside where they should be, or glancing at the RPM gauge.

 

I have been in my first turbine and a couple thousands hours beyond that. I don't do a lot of primary training in turbines, so it is more rare, but I have seen even the most experienced pilots exceed the torque limits when they screw up an auto.

 

And Joe, If you are an instructor, you do it all the time and nothing has happened to you. When you have a bit more experience, things start to slow down and you will realize that it is happening all the time, but you just haven't noticed before.

[Witch]

Coming in hot and making a big flare is the most dangerous way you can make an approach, and IMO is stupid.

Gomer is so correct here.

 

I recall a Youtube vid that shows a Blackhawk coming in so very hot. The copter flares into a quick stop and loses all lift resulting in a fall of about twenty feet. The bird then rolled into a tree and the blades actually cut the tree down before the blades became a tangled mess. Worlds largest chainsaw?

 

Anyhow, if someone can find the link?

 

I remember something that the DPE said during my checkride; "You're not in a hurry, slow down." That seems the way to go.

 

Later

Edited October 19, 2008 by Witch

[JDHelicopterPilot]

Joeschmoe and Darren,

 

I have discussed this extensively with Schweitzer and Robinson reps. If they were worried about intermittent pulls of the MP beyond the limitations, they would have an inspection requirement. They don't.

 

And I guarantee you that I can take any instructor here, put them close to gross weight in an R22 or 300C, and catch them exceeding the MAP limits recovering from botched autos, or with a new student learning to hover, quick stops, etc. And I bet that instructor won't even know they exceeded the limits. So, anyone who says they never exceed the limits during training flight either isn't letting the student fly enough, or doesn't have the experience yet to know they are exceeding the limits. If a student is slow at getting on the power in a power recovery and the RPM drops even a little, the MAP has to go way beyond what it takes to hover to get that rpm back. The problem is, your eyes are not on the MAP gauge. They are either outside where they should be, or glancing at the RPM gauge.

 

I have been in my first turbine and a couple thousands hours beyond that. I don't do a lot of primary training in turbines, so it is more rare, but I have seen even the most experienced pilots exceed the torque limits when they screw up an auto.

 

And Joe, If you are an instructor, you do it all the time and nothing has happened to you. When you have a bit more experience, things start to slow down and you will realize that it is happening all the time, but you just haven't noticed before.

 

Sorry but I don't agree. While yes, I am sure some have exceeded limits when it became needed due to something going wrong. That's fine, do what you have to in order to ensure the safety of yourself and passengers. What I don't agree with is advocating that we do it all the time and to just accept it. Just because there isn't an inspection for the R-22 or 300, what about if I exceed the limits in my A119 or AS350? What's the difference? It's a helicopter just like others. It can be loaded to max gross weight and be just as limited on power as an R-22 or a 300.

 

CFI's should be able to catch something going wrong before it comes to having to yank the guts out of the engine. If they find themselves doing so on a regular basis I have to say somthing isn't right.

 

That's my $.02, I think we can agree to disagree on this one.

[RockyMountainPilot]

Whats the difference between an A119 and AS350 to an R22 and 300C?

 

1. The R22 and 300C are used for primary training and are near gross weight while doing so.

2. The A119 and AS350 are much heavier, have more inertia in the rotors, and are typically flown by professional pilots, especially if they are operated near gross weight.

3. The AS350 and A119 have inspection requirements if you exceed certain limits.

 

If you think a CFI should be able to catch everything before it goes wrong, you are either not a CFI, or haven't trained a lot of people. If you think you have never exceeded the limits during training, you are not paying attention to your aircraft.

[HelliBoy]

+1 to that RMP. I think the gist of what JD is saying though is that once you do become an experienced instructor you start to learn when and where those exceedences are likely to occur and take extra measures to prevent things going pear shaped in the first place. When I started instructing my students exceeded limitations on a regular basis (not seriously, thankfully) but now its very rare that I let it happen because they mostly all do it in the same situations. (Im not a controls nanny either) I think it speaks to what you said about things slowing down with experience.